var name = 'ziheng'

foo(123)
function foo (num){
    console.log(`m`, m);
    var m = 1
    var n = 2
    console.log("hello");
    function bar (){
        console.log(name);
        
    }
    bar()
}
var num1 = 20
var num2 = 30
var num3 = num1 + num2

// console.log(`num3`, num3);